Drive for opening and closing a vehicle flap

ABSTRACT

A flap drive for a flap includes two identical lever joint arrangements which are arranged in pairs at a distance from one another. The flap can be moved out of its closing position into its opening position and back by the flap drive. In this case, the lever joint arrangements are articulated pivotably with one of their ends in each case on a side region of the flap and with their other ends at a fixed location on the motor vehicle. The mutually corresponding pivot axes of the articulation points extend coaxially to one another. Movement transmission devices for the pivotable drive of a driven lever of each lever joint arrangement are guided by a common motive drive unit, the driven levers being articulated at a fixed location on the motor vehicle.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The invention relates to a drive for moving a flap, in particular forthe rear flap or tailgate of a motor vehicle, out of its closingposition into its opening position and back, the drive having twoidentical lever joint arrangements which are arranged in pairs at adistance from one another, one end of the lever joint arrangements beingarticulated pivotably on a side region of the lever joint arrangementsproximate the flap and an other end of the lever joint arrangementsbeing articulated pivotably at a fixed location on the motor vehicle ora component of the motor vehicle, the mutually corresponding pivot axesof the articulation points extending coaxially to one another.

2. Description of the Related Art

In flap drives for opening a rear flap on a motor vehicle, lever jointarrangements comprising parallelogram lever joint arrangements are usedto move a rear flap out of a vertically oriented closing position ofapproximately vertical attitude in an arc into a likewise verticallyoriented opening position. For this purpose, the two lever jointarrangements are driven by two separate drive units. As a result of thetwo drive units, the flap drive is complicated and requires a largeamount of construction space.

Furthermore, the use of the two separate drive units easily leads to anunequal drive and consequently to an asymmetric application of torque onthe two sides of the flap, such that distortions of the flap may occurduring the movement drive.

SUMMARY OF THE INVENTION

An object of the present invention is to provide a flap drive for a rearflap, i.e., tailgate or hatch, of a motor vehicle, which requires a lowoutlay in structural terms and a small amount of construction space andby which avoids distortions of the flap during the movement drive of therear flap.

The object is achieved, according to the present invention, by movementtransmission means arranged at each lever joint for the pivotable driveof a lever of each lever joint arrangement, the driven lever beingarticulated at a fixed location on the motor vehicle or a component ofthe motor vehicle, wherein the movement transmission means at each leverjoint are guided by a common motive, in particular, an electromotivedrive unit.

This design allows the drive to apply torque symmetrically on both sidesof the flap during the movement travel of the flap, so that a distortionof the flap during movement is avoided.

The one drive unit requires only a small amount of construction spaceand a low outlay in structural terms.

The levers articulated at a fixed location on the motor vehicle or acomponent of the motor vehicle may be pivotable out of their closingposition into their opening position through various angles, but, inparticular, through approximately 180°. A wide range of movement of theflap out of its closing position into its opening position isconsequently achieved.

A stable hold of the flap is achieved when the lever joint arrangementsare four-bar lever arrangements.

If the four-bar lever arrangements are at least approximatelyparallelogram lever arrangements, a flap movement with an at leastlargely identical orientation of a plane of the flap during the entiremovement travel takes place. The necessary space through which the flapis moved is consequently also particularly small.

A particularly simple motive drive unit consists of a rotary drive.

The construction of the inventive drive may be realized in aparticularly simple manner when a rigid drive shaft can be drivenrotatably by a rotary drive, wherein the rigid drive shaft extendscoaxially to one of the pivot axes of the fixed-location articulationpoints on the motor vehicle or a component of the motor vehicle and therigid drive shaft is connected fixedly in terms of rotation in each caseto one of the mutually corresponding levers of the lever jointarrangements.

So that the torque to be applied by the rotary drive can be reducedand/or so that the rotary drive can be arranged at a point further fromthe flap, a rigid drive shaft can be driven rotatably by the rotarydrive, wherein the rigid drive shaft extends parallel to one of thepivot axes of the fixed-location articulation points on the motorvehicle or a component of the motor vehicle and the rigid drive shaft isconnected via gear units in each case to one of the mutuallycorresponding levers of the lever joint arrangement, these levers beingcapable of being driven pivotably about the pivot axis by the gearunits.

The gear units may be chain gear units or toothed-belt gear units whichhave a driving wheel arranged fixedly on the drive shaft and a drivewheel arranged fixedly in terms of rotation on the lever, a chain or atoothed belt being guided around the driving wheel and drive wheel.

In a further embodiment, flexible shafts may be driven rotatably by therotary drive. Each of the flexible shafts extend to one of the pivotaxes of the fixed-location articulation points on the motor vehicle or acomponent of the motor vehicle and by means of which in each case onelever of the lever joint arrangement can be driven rotatably.

This embodiment allows, with high degrees of freedom, the arrangement ofthe drive unit at a distant point.

To reduce the torque to be applied by the drive unit, each flexibleshaft is capable of driving rotatably the lever assigned to it by one ormore gear units.

The required torque to be applied is in this case is particularly lowwhen the gear unit is an epicyclic gear unit or a worm gear unit.

In a further embodiment, the motive drive unit may be a rope-tractiondrive. In this embodiment, two ropes leading to and wound onto ropepulleys can be driven tractively. The rope pulleys are arranged in eachcase coaxially to one of the pivot axes of the fixed-locationarticulation points on the motor vehicle or a component of the motorvehicle and are connected fixedly in terms of rotation in each case toone of the mutually corresponding levers of the lever jointarrangements.

This embodiment, too, makes it possible, with high degrees of freedom,to arrange the drive unit at a point distant from the flap to be driven.

One or two driving rope pulleys, onto which one or two of the ropes canbe wound, may be capable of being driven rotatably by means of therope-traction drive.

Alternatively, one or two racks, to which one or two of the ropes arefastened tractively, may be driven movably in their longitudinaldirection by the rope-traction drive.

If in each case two ropes are guided from the driving rope pulley or therack to a rope pulley and can be wound in the opposite direction ontothe driving rope pulley or can be tractioned from the rack and can bewound in the opposite direction onto the rope pulley and unwound, thenthe flap drive can execute not only an opening movement of the flap, butalso a closing movement. For this purpose, it is necessary merely for areversal of the direction of movement of the rope pulley or of the rackto take place.

To reduce the torque to be applied by the motive drive unit, the drivingrope pulley or the rack may be capable of being driven by the motivedrive unit via a gear unit, in particular a reduction gear unit.

In a further embodiment, a lever of each lever joint arrangement, whichis articulated at a fixed location on the motor vehicle or a componentof the motor vehicle, may have a first auxiliary lever which isarticulated with one end region on the lever at a distance from aconnecting line between the fixed-location articulation point of thelever on the motor vehicle or a component of the motor vehicle and thearticulation point of the lever on the flap, so that the first auxiliarylever is pivotable about a first joint axis parallel to the pivot axesof the lever. The first auxiliary lever is, in the region of theconnecting line, capable of butting against a first abutment at adistance from the fixed-location articulation point. At its other endregion, the first auxiliary lever can be acted upon with force by afirst movement means approximately in the direction of extent of thelever in one of the closing position or the opening position.

The arrangement of the first auxiliary lever avoids a dead centerposition of the drive, which would otherwise occur in the case of largeopening angles of the levers. Furthermore, the torque acting upon thelever can be kept largely constant.

To allow a movement drive in both directions of movement, the leverarticulated at a fixed location on the motor vehicle or a component ofthe motor vehicle may have a second auxiliary lever which is articulatedwith one end region on the lever at a distance from the connecting linebetween the fixed-location articulation point of the lever on the motorvehicle or a component of the motor vehicle and the articulation pointof the lever on the flap on that side of the connecting line which islocated opposite the first joint axis, so as to be pivotable about asecond joint axis parallel to the pivot axes of the lever. The secondauxiliary lever is, in the region of the connecting line, capable ofbutting against a second abutment at a distance from the fixed-locationarticulation point. At its other end region, the second auxiliary levercan be acted upon with force by second movement means approximately inthe direction of extent of the lever in the other of the closingposition or the opening position.

In this case, a flat construction of the flap drive which savesconstruction space is achieved when the first auxiliary lever and thesecond auxiliary lever are arranged on sides of the lever which arelocated opposite to one another.

The first and second auxiliary lever may have different lengths.

If the first and second abutment are arranged approximately coaxially toone another and the first and the second auxiliary lever areapproximately of equal length, then identical kinematic conditions canbe achieved both for the opening operation and for the closingoperation, along with a small overall size.

The first and/or the second movement means may be ropes of arope-traction device and/or pneumatic springs.

Where pneumatic springs are concerned, these are also at the same timethe drive unit. In this case, each lever joint arrangement may also beassigned a pneumatic spring.

To prevent an obstacle located in the path of movement of the flap frombeing pinched and damaged, a resistance obstructing a pivoting movementof the lever arrangement may be capable of being detected and acorresponding resistance signal can be capable of being fed toelectronics by an obstacle recognition. In response to a resistancesignal, the drive unit may be stopped in the one drive direction.

So that an obstacle of this kind may be released again immediately, thedrive unit can be capable of being changed over, so as to move over adefined distance opposite to the one drive direction, by means of theelectronics when a resistance signal is received.

For this purpose, the obstacle recognition may have a position sensor,in particular a potentiometer, which detects the respective position ofone of the levers of the lever arrangement and by means of which acorresponding position signal can be generated and can be fed to theelectronics, and, in the electronics, the running time actually requiredto reach the respective position can be compared with a definedpredetermined running time for reaching the respective position, inwhich case, when the actual running time overshoots the predeterminedrunning time, the resistance signal can be generated.

The detection of the position of one of the levers of the leverarrangement may also take place indirectly, in that, for example, theposition of the drive unit is detected by a sensor, such as, forexample, a Hall sensor. For this purpose, the sensor may be integratedinto the drive unit.

When a movement of the flap is not effected by the motive drive unit,but by the action of manual force, it is advantageous if a coupling,which can be opened when the flap is acted upon manually to move to movethe flap, is arranged between the motive drive unit and the movementtransmission means or between the movement transmission means and thatlever of the lever joint arrangement which is capable of being drivenpivotably by them.

Other objects and features of the present invention will become apparentfrom the following detailed description considered in conjunction withthe accompanying drawings. It is to be understood, however, that thedrawings are designed solely for purposes of illustration and not as adefinition of the limits of the invention, for which reference should bemade to the appended claims. It should be further understood that thedrawings are not necessarily drawn to scale and that, unless otherwiseindicated, they are merely intended to conceptually illustrate thestructures and procedures described herein.

BRIEF DESCRIPTION OF THE DRAWINGS

In the drawing, wherein like reference characters denote similarelements throughout the several views:

FIG. 1 a diagrammatic perspective illustration of a first embodiment ofa flap drive according to the present invention;

FIG. 2 is a diagrammatic perspective illustration of a second embodimentof a flap drive according to the present invention;

FIG. 3 is a diagrammatic perspective illustration of a third embodimentof a flap drive according to the present invention;

FIG. 4 is a diagrammatic perspective illustration of a fourth embodimentof a flap drive according to the present invention;

FIG. 5 is a diagrammatic perspective illustration of a fifth embodimentof a flap drive according to the present invention;

FIG. 6 is a schematic view of a rope-traction drive of the flap driveaccording to FIG. 5;

FIG. 7 is a further rope-traction drive for use in the flap driveaccording to FIG. 5;

FIG. 8 is a perspective view of one of the lever joint arrangements ofthe flap drive according to FIG. 5 in the closing position;

FIG. 9 is the lever joint arrangement according to FIG. 8 in a middleopening position;

FIG. 10 is the lever joint arrangement according to FIG. 8 in the fullopening position;

FIG. 11 is an enlarged perspective view of a detail of the lever jointarrangement according to FIG. 8 in a position between the closingposition and the middle opening position;

FIG. 12 is an enlarged perspective view of a detail of the lever jointarrangement according to FIG. 8 in a position between the middle openingposition and the full opening position;

FIG. 13 is an enlarged perspective view of a detail of the lever jointarrangement according to FIG. 8 in the full opening position;

FIG. 14 is a perspective rear view of the lever joint arrangementaccording to FIG. 13 in the full opening position;

FIG. 15 is a perspective rear view of the lever joint arrangementaccording to FIG. 12 in the position between the middle opening positionand the full opening position;

FIG. 16 is a perspective rear view of the lever joint arrangementaccording to FIG. 11 in the position between the middle closing positionand the middle opening position; and

FIG. 17 is a block diagram of a obstacle recognition for the flap driveaccording to the present invention.

DETAILED DESCRIPTION OF THE PRESENTLY PREFERRED EMBODIMENTS

The flap drives illustrated in the Figs. have two identicalparallelogram lever arrangements 1 and 1′ arranged in pairs at adistance from and parallel to one another. Each of the parallelogramlever arrangements 1, 1′ includes two mutually parallel levers 2, 3 and2′, 3′, respectively. The parallel levers 2 and 2′ have an end 4 and theparallel levers 3, 3′ have an end 5 that are articulated pivotably at afixed location on a motor vehicle by a body lever 12, the correspondingpivot axes 6 and 7 of the articulation points extending coaxially to oneanother. Lever 2 is fixed at an approximately vertical distance fromlever 3 and lever 2′ is fixed at an approximately vertical distance fromlever 3′.

The two other ends 8 and 9 of the levers 2, 3 and 2′, 3′ are articulatedon a flap lever 11 fixedly connected to a flap 10 (illustrated by brokenlines in FIG. 1).

In the exemplary embodiment of FIG. 1, a rigid drive shaft 13, which isconnected fixedly in terms of rotation to the levers 3 and 3′, extendscoaxially to the pivot axis 7. An electromotive rotary drive 14 operatesto rotate the drive shaft 13. The levers 3 and 3′ are driven pivotablywith the drive shaft 13 through about 180°. Due to the pivoting of thelevers 3 and 3′, the two parallelogram lever arrangements 1 and 1′ arepivoted and, thus, the flap 10, while maintaining its verticallyoriented plane, moves in an arc out of a lower closing position into anupper opening position and, with the rotary drive being reversible, alsoback again.

To assist the opening movement, the levers 3 and 3′ or 2 and 2′ may beacted upon in the direction of the opening position by pneumaticsprings, not illustrated in FIG. 1.

For the manual movement of the flap 10 from the closing position to theopening position, or vice-versa, a coupling may be arranged between therotary drive 14 and the drive shaft 13 which is opened when the flap 10is moved manually and which thus separates the frictional connectionbetween the rotary drive 14 and drive shaft 13.

In the exemplary embodiment of FIG. 2, there extends parallel to thepivot axes 6 and 7 a rigid drive shaft 15 which carries rotationallyfixed toothed-belt pulleys 16 and which can be driven rotatably by meansof a rotary drive 14 via the coupling between the rotary drive 14 andthe drive shaft 15.

Further toothed-belt pulleys 17 are connected fixedly in terms ofrotation to the levers 3 and 3′ coaxially to the pivot axis 7 in theplane of the toothed-belt pulleys 16 so as to be located opposite thesein parallel.

Around the toothed-belt pulleys 16 and 17 located opposite one anotherare guided toothed belts 18 which transmit the rotational movement ofthe drive shaft 15 to the toothed belt pulleys 17 and drive the levers 3and 3′ and consequently the parallelogram lever arrangements 1, 1′pivotably, so that the flap 10 can be moved between its closing positionand its opening position.

In FIG. 3, two flexible shafts 19 can be driven rotatably for thepivoting drive of the parallelogram lever arrangements 1 and 1′ by therotary drive 14. Each of the flexible shafts 19 extends to one of thelevers 3 and 3′ and which drive these pivotably about the pivot axis 7via epicyclic gear units 20.

Instead of the epicyclic gear units 20, FIG. 4 shows that the levers 3and 3′ are driven pivotably about the pivot axis 7 by two flexibleshafts 19 via worm gear units 21.

In the exemplary embodiment of FIG. 5, rope pulleys 22 and 22′ arearranged fixedly in terms of rotation on the levers 3 and 3′ coaxiallyto the pivot axis 7. Ropes 23 and 23′ are guided around the rope pulleys22 and 22′. The ropes 23, 23′ can be driven tractively by a reversibleelectromotive rope-traction drive 24. As a result of the tractivemovement, the ropes 23 and 23′ drive the rope pulleys 22 and 22′rotatably and thus pivot the levers 3 and 3′ and consequently theparallelogram lever arrangements 1 and 1′.

As illustrated in FIG. 6, the rope-traction drive 24 possesses a drivingrope pulley 25 which can be rotatably driven reversibly by a rotarydrive, not illustrated. As a result, the ropes 23 and 23′ can be woundonto the driving pulley 25 and unwound and the ropes 23 and 23′ can thusbe driven tractively.

Alternatively to the rope pulleys 22 and 22′, according to FIG. 7, tworacks 26 and 26′ having mutually facing toothings, can be arrangedparallel to one another that are capable of being driven movably intheir longitudinal extent in opposite directions by a driving wheel 27engaging into the toothings of the two racks 26 and capable of beingdriven reversibly by a rotary drive.

In the exemplary embodiment of FIGS. 8 to 16, in which only oneparallelogram lever arrangement 1 is illustrated, a first auxiliarylever 28 is articulated with one end on the lever 3 in the region of theend 5 of the latter so as to be pivotable about a first joint axis 29parallel to the pivot axis 7. The first joint axis 29 is located at adistance from a connecting line 30 between the pivot axis 7 and thearticulation point of the lever 3 on the flap 10.

A first abutment 31 is arranged on the lever 3 and projects into thepivoting range of the first auxiliary lever 28, approximately on theconnecting line 30 and approximately at the same height as the firstjoint axis 29. The free end of the first auxiliary lever 28 hasarticulated on it, at an articulation point 34, one end of a pneumaticspring 32. A piston rod 33 which projects out of the other end of thepneumatic spring is articulated with its free end on a fixed-locationcomponent of the motor vehicle. The distance between the first jointaxis 29 and the articulation point 34 is approximately twice as great asthe distance between the connecting line 30 and the first joint axis 29.

The closing position of the flap drive is illustrated in FIG. 8. As aresult of the opening of a flap lock, not illustrated, by means of whichthe flap 10 is held in the closing position on the body of the motorvehicle, the pneumatic spring 32, in its extension direction, acts uponthe first auxiliary lever 28 at the articulation point 34. In this case,the first auxiliary lever 28 is supported with its middle region on thefirst abutment 31, so that a torque is exerted on the first auxiliarylever 28 by the pneumatic spring 32. This torque produces a pivoting ofthe first auxiliary lever 28 anti-clockwise around the first abutment31, with the result that the lever 3 is also driven to pivotanti-clockwise via the first joint axis 29.

When a middle opening position, illustrated in FIG. 9, is reached beyondthe position shown in FIG. 11, there is no longer any support of thefirst auxiliary lever 28 on the first abutment 31. Further action uponthe first auxiliary lever 28 by the pneumatic spring 32 then producestractive action upon the first auxiliary lever 28 which generates atorque about the pivot axis 7 and rotates the lever 3 furtheranti-clockwise, until the full opening position illustrated in FIGS. 10and 13 is reached beyond the position shown in FIG. 12.

As can be seen particularly in FIGS. 14 to 16, a second auxiliary lever35, which corresponds approximately to the first auxiliary lever 28, isarranged on that side of the lever 3 which is located opposite the firstauxiliary lever 28.

This second auxiliary lever 35 corresponds approximately to the firstauxiliary lever 28 and is articulated on the lever 3 pivotably about asecond joint axis 36 which extends parallel to the pivot axis 7approximately at the same distance from the connecting line 30 as thefirst joint axis 28, but on the other side of the connecting line 30.

A second abutment 37 projects approximately coaxially to the firstabutment 31 into the pivoting range of the second auxiliary lever 35.

Fastened to the free end of the second auxiliary lever 35 is one end ofa rope 23 which extends approximately parallel to the pneumatic spring32 and which can be driven tractively by a rope-traction drive, such asthe drives illustrated, for example, in FIGS. 6 to 8.

As shown in FIG. 14, in the full opening position, the second auxiliarylever 35 bears with its middle region against the second abutment 37, sothat, when the rope 23 is acted upon with traction, a torque is exertedon the second auxiliary lever 35 and, via the second joint axis 36, alsoon the lever 3, thus producing a pivoting of the lever 3 counter to theforce of the pneumatic spring 32 beyond the position illustrated in FIG.15 into the middle opening position. From there on, the second auxiliarylever 35 is acted upon with traction in an equivalent way to the openingoperation, with the result that a torque about the pivot axis 7 isgenerated and the lever 3 is moved further on beyond the positionillustrated in FIG. 16 into the closing position.

FIG. 17 shows an obstacle recognition device 100 to prevent an obstaclelocated in the path of movement of the flap 10 from being pinched anddamaged. A position sensor 110 such as, for example, a potentiometer isused to detect a resistance obstructing a pivoting movement of the leverarrangement in one drive direction. A corresponding resistance signalcan be fed to electronics 120. In response to a resistance signal, theelectronics 120 may be operable for stopping the drive unit in the onedrive direction.

So that an obstacle of this kind may be released again immediately, thedrive unit may be changed over, so as to move over a defined distanceopposite to the one drive direction, by means of the electronics 120when a resistance signal is received.

The position sensor 110 may detect the respective position of one of thelevers of the lever arrangement and generate a corresponding positionsignal which is fed to the electronics 120. The running time actuallyrequired to reach the respective position is compared with a definedpredetermined running time for reaching the respective position in theelectronics 120. When the actual running time overshoots thepredetermined running time, the resistance signal is generated. Thedetection of the position of one of the levers of the lever arrangementmay also take place indirectly, in that, for example, the position ofthe drive unit is detected by a sensor, such as, for example, a Hallsensor. For this purpose, the sensor may be integrated into the driveunit.

Thus, while there have shown and described and pointed out fundamentalnovel features of the invention as applied to a preferred embodimentthereof, it will be understood that various omissions and substitutionsand changes in the form and details of the devices illustrated, and intheir operation, may be made by those skilled in the art withoutdeparting from the spirit of the invention. For example, it is expresslyintended that all combinations of those elements which performsubstantially the same function in substantially the same way to achievethe same results are within the scope of the invention. Moreover, itshould be recognized that structures and/or elements shown and/ordescribed in connection with any disclosed form or embodiment of theinvention may be incorporated in any other disclosed or described orsuggested form or embodiment as a general matter of design choice. It isthe intention, therefore, to be limited only as indicated by the scopeof the claims appended hereto.

1. A flap drive for driving a rear flap of a motor vehicle, comprising:first and second lever joint arrangements arranged at a distance fromone another and by which the flap is movable from a closing position toan opening position and back to the closing position, each of said firstand second lever joint arrangements having a first side regionconnectable to the flap and a second side region connectable at a fixedlocation on the motor vehicle or a component of the motor vehicle, saideach of said first and second lever joint arrangements having one endarticulated pivotably about pivot axes at said first side region andanother end articulated pivotably about pivot axes at said second sideregion, the mutually corresponding pivot axes extending coaxially to oneanother, said each of said first and second lever joint arrangementscomprising a driven lever articulated at an articulation point at one ofsaid pivot axes at said second side region an articulated at anotherarticulation point at one of said pivot axes at said first side region;and a common motive drive unit for guiding a movement transmission unitfor the pivotable drive of each of said driven levers of said first andsecond lever joint arrangements.
 2. The flap drive of claim 1, whereinsaid driven levers of said first and second lever joint arrangements arepivotable out of the closing position into the opening position throughapproximately 180°.
 3. The flap drive of claim 1, wherein each of saidfirst and second lever joint arrangements are four-bar leverarrangements.
 4. The flap drive of claim 3, wherein said four-bar leverarrangements are parallelogram lever arrangements.
 5. The flap driveaccording of claim 1, wherein said motive drive unit is a rotary drive.6. The flap drive of claim 5, further comprising a rigid drive shaftextending coaxially to one of the pivot axes of the articulation pointsand connected fixedly with respect to rotation to each of said drivenlevers of said first and second lever joint arrangements, said rotarydrive being connected to said rigid drive for rotating said rigid drive.7. The flap drive of claim 5, further comprising a rigid drive shaftextending parallel to one of the pivot axes of said articulation points,gear units connected to said rigid drive shaft, each of said gear unitsbeing connected to a corresponding of said driven levers of said firstand second lever joint arrangements, said rigid drive being rotatablydriven by said rotary drive, wherein said driven levers are pivotableabout the pivot axis by said gear units in response to rotation of saidrigid drive.
 8. The flap drive of claim 7, wherein said gear unitscomprise one of chain gear units and toothed-belt gear units, each ofsaid gear units comprising a driving wheel arranged fixedly on the driveshaft, a drive wheel arranged fixedly with respect to rotation on acorresponding one of said driven levers, and one of a chain and atoothed belt guided around said driving wheel and said drive wheel. 9.The flap drive of claim 5, further comprising flexible shafts rotatabledrivable by said rotary drive, each of said flexible shafts extending toone of the pivot axes of said articulation points for rotatably drivingsaid driven levers of said first and second lever joint arrangements.10. The flap drive of claim 9, wherein each of said driven levers isconnected to one of said flexible shafts by a gear unit such that eachof said flexible shafts rotatably drives a corresponding one of saiddriven levers by said gear unit.
 11. The flap drive of claim 10, whereineach of said gear units comprises one of an epicyclic gear unit and aworm gear unit.
 12. The flap drive of claim 5, further comprising ropepulleys arranged coaxially to the pivot axes of said articulationpoints, each of said rope pulleys being connected fixedly with respectto rotation to a corresponding one of said driven levers of said firstand second lever joint arrangements, wherein said motive drive unit is arope-traction drive connected for tractively driving two ropes woundonto said rope pulleys.
 13. The flap drive of claim 12, wherein saidrope-traction drive comprises at least one driving rope pulley fortractively driving at least one of said ropes.
 14. The flap drive ofclaim 12, wherein said rope-traction drive comprises at least one rackconnected to one of said ropes, said at least one rack beinglongitudinally driven by said rope-traction drive.
 15. The flap drive ofclaim 13, wherein each of said two ropes is guided from the driving ropepulley to a corresponding one of said rope pulleys, each of said ropesis wound in one direction onto said driving rope pulley and wound in theopposite direction onto a corresponding one of said rope pulleys. 16.The flap drive of claim 14, wherein said rope traction drive comprisestwo racks, each of said racks being connected to one of said two ropes,wherein each of said ropes is tractioned from the rack and wound in theopposite direction onto said rope pulleys.
 17. The flap drive of claim13, further comprising a reduction gear unit arranged between saidmotive drive unit and said driving rope pulley such that said drivingrope pulley is driven by said motive drive unit by said reduction gearunit.
 18. The flap drive of claim 14, further comprising a reductiongear unit arranged between said motive drive unit and said rack suchthat said rack is driven by said motive drive unit by said reductiongear unit.
 19. The flap drive of claim 1, wherein a connecting lineextends from said articulation point of said driven lever at said firstside and said articulation point of said driven lever at said secondside, each of said driven levers of said first and second lever jointarrangements comprises a first auxiliary lever having an end regionarticulated on said each of said each of said driven levers at adistance from said connecting line, said articulated end region of saidfirst auxiliary lever being arranged between said articulation point ofsaid each of said driven levers at said first side region and saidarticulation point of said each of said driven levers at said secondside region, such that said first auxiliary lever is pivotable about afirst joint axis parallel to said pivot axis of said at least one ofsaid driven levers, a first abutment being arranged on said each of saiddriven levers in a region of said connecting line and projecting into apivoting range of said first auxiliary lever such that said firstauxiliary lever butts against said first abutment at a distance fromsaid articulation point of said driven lever at said second side region,wherein the other end region of said first auxiliary lever isconnectable to a first movement device at an engagement point whichproduces a force directed approximately in the direction of alongitudinal extension of said driven lever in one of the closingposition and the opening position.
 20. The flap drive of claim 19,wherein said each of said driven levers includes a second auxiliarylever having an end region articulated on said each of said drivenlevers at a distance from said connecting line between said articulationpoint of said each of said driven levers at said first side region andsaid articulation point of said each of said driven levers at saidsecond side region on a side of said connecting line which is locatedopposite said first joint axis, such that said second auxiliary lever ispivotable about a second joint axis parallel to said pivot axes of saideach of said driven levers, a second abutment being arranged on saideach of said driven levers in a region of said connecting line andprojecting into a pivoting range of said second auxiliary lever suchthat said second auxiliary lever butts against said second abutment at adistance from said articulation point of said driven lever at saidsecond side region, wherein the other end region of said secondauxiliary lever is connectable to a second movement device at anengagement point, said second movement device produces a force directedapproximately in the direction of a longitudinal extension of saiddriven lever in the other one of said closing position and said openingposition.
 21. The flap drive of claim 20, wherein said first auxiliarylever and said second auxiliary lever are arranged on opposing sides ofsaid each of said levers.
 22. The flap drive of claim 21, wherein saidfirst abutment and said second abutment are arranged approximatelycoaxially to one another.
 23. The flap drive of claim 21, wherein saidfirst and the second auxiliary levers are approximately of equal length.24. The flap drive of claims 20, wherein at least one of said first andsecond auxiliary levers includes a middle region butting against saidcorresponding one of said first and second abutments, said middle regionbeing arranged between said joint axis and the engagement point of saidat least one of said first and second auxiliary levers.
 25. The flapdrive of claims 20, wherein said first and second movement devicescomprise ropes of a rope-traction drive.
 26. The flap drive of claim 20,wherein said first and second movement devices comprise pneumaticsprings.
 27. The flap drive of claim 1, further comprising an obstaclerecognition for detecting a resistance obstructing a pivoting movementof one of said first and second lever arrangements in one drivedirection and feeding a corresponding resistance signal to electronicsfor stopping said drive unit in the one drive direction.
 28. The flapdrive of claim 27, said electronics comprising means for moving thedrive unit over a defined distance opposite to the one drive directionwhen the resistance signal is received.
 29. The flap drive of claim 27,wherein said obstacle recognition includes a position sensorpotentiometer for detecting a respective position of one of said firstand second lever arrangements for generating a corresponding positionsignal fed to said electronics, said electronics comprising means forcomparing the running time actually required to reach a respectiveposition with a defined predetermined running time for reaching therespective position, and means for generating the resistance signal whenthe actual running time is greater than the predetermined running time.30. The flap drive according claim 1, further comprising a couplingarranged between said motive drive unit and said levers of said firstand second lever joint arrangements, said coupling being openable sothat the flap is manually movable.